1. Field of the Invention (Technical Field)
The present invention relates to determining one's location within a building, particularly one's location within a user-occupied room of a building.
2. Description of Related Art
Certain projects require that one accurately locate oneself within a building, such as when taking an environmental sample within a building. Global Positioning Systems (GPS) and Radio Frequency (RF) triangulation methods do not work well within many buildings of interest. The present invention employs a digital map of a building's interior on a handheld computer/personal data assistant (PDA). To provide positional information when RF triangulation methods fail, the present invention provides an innovative method of, software for, and apparatus for positioning using a laser rangefinder and a PDA.
Current laser rangefinders simply report the distance from the laser instrument to an object the laser is pointed at. There is no provision for translating these distance measurements to local x,y positions and then to global x,y positions as is done in the present invention.
Currently available positioning systems rely on triangulation. Systems include fixed ultrasonic transducers and systems with fixed RF receivers. These systems suffer from a need for a calibrated, fixed sensor infrastructure and uniform penetration of the locator signals. The present invention is ad-hoc in that the transmitter, receiver and processor are mobile, and the invention is not affected by RF opacity.